This invention relates generally to in-line assembly machines. More particularly, the invention relates to an in-line assembly machine which is capable of commonly actuating tooling associated with the machine at a plurality of work stations.
Automated assembly machines have the capability of rapidly assembling a wide variety of component parts. For example, light bulbs, electrical components, disposable cigarette lighters and small pumps and motors are often assembled by such machines.
Most conventional assembly machines are generally of two basic designs. The first type, commonly called the rotary assembly machine, is described in U.S. Pat. No. 3,065,530 which is assigned to the Swanson-Erie Corporation. One of the most advanced machines of this type includes two circular tool plates designed to reciprocate above an intermittently-rotating circular indexing turret. A number of work stations are positioned around the periphery of the turret, a separate article being assembled at each such station.
The reciprocation of the tool plates causes actuation of tooling mounted to these plates, thus performing a wide variety of operations at the work stations, such as, screwing, riveting, punching or merely sensing the proper position of the parts at the stations. As explained in detail in U.S. Pat. No. 3,065,530, the use of two reciprocating tool plates enables the performance of more complex operations with greater adaptability than possible with machines having only a single tool plate.
Perhaps the single biggest reason for the success of the rotary assembly machine is its versatility. However, one of its limitations is that when a large number of operations are required to assemble an item, several rotary machines may have to be combined. In order to overcome the necessity of using several assembly machines, a so-called in-line type assembly machine is often utilized. This machine, which comprises the second basic type of assembly machine, typically includes a continuous, linked or articulated belt which intermittently indexes the article to be assembled through the required number of work stations. These work stations are ordinarily lined up on one or both sides of the machine, and occassionally on one or both ends.
The tooling at each work station is typically actuated by one or more cams mounted to lower and upper horizontal camshafts. When a simple operation is performed, such as merely sensing the position of the parts at the work station, it may be possible to use a single cam, which would ordinarly be mounted to one of the camshafts. However, when other more complex operations are required, such as those involving two motions, one or more additional cams are used.
For example, typical pick-and-place operations often involve outward/inward lateral motion as well as up/down vertical motion. The pickup cartridge is normally carried by the tooling associated with one of the cams, and therefore is caused to vertically reciprocate upon the rotation of this cam. The cartridge is raised or lowered to the proper elevation by the first cam and associated linkage. At the same time, the cartridge is driven laterally through the tooling associated with another of the cams. Thus, after picking up the part to be assembled, the cartridge is displaced laterally inward toward the work station by the second cam. This type of operation is exceedingly difficult with a single cam.
Since each work station therefore requires at least one and typically two or three of its own tooling actuating cams mounted to one of two separate camshafts, the complexity and thus the cost of such a machine is formidable. Another disadvantage of the complex tooling drive mechanisms required with conventional in-line machines is that the tooling and follower mechanisms are ordinarily not interchangeable between rotary and in-line assembly machines.
In order to eliminate some of the cams required with in-line machines, a so-called rise and fall bar has occasionally been utilized. This bar runs the length of the machine, on one or both sides, and provides tooling drive for performing simple operations such as sensing or stripping, often in cooperation with individual work station cams. However, upper and lower camshafts are still required in order to provide tooling actuating drive for the other work stations where more complex operations are being performed.
Accordingly, it is an object of this invention to provide an improved in-line assembly machine which eliminates the need for two camshafts with separate tooling drive mechanisms for each work station. Another objective is the provision of an improved in-line assembly machine in which the tooling is interchangeable with tooling used on rotary assembly machines. Yet another objective is the provision of an in-line assembly machine which is simpler and therefore less expensive and more reliable than conventional designs. Other objectives will become apparent as this description proceeds.